There is little research on students' engagement in physical activity in middle school physical education (PE). We observed student activity, lesson context, and teacher behavior in 430 PE lessons taught by 126 teachers in 24 schools. Variables were analyzed by mixed-model nested analyses of covariance. Boys were more active than girls overall and during skill drills, game play, and free play. Student activity varied by lesson context, with fitness activities producing the most activity. Class size was negatively associated with student activity. Daily PE contributed a weekly total of 25 min of vigorous activity and 83 min of moderate-to-vigorous activity—much less than national objectives. Results suggest that numerous opportunities exist for increasing student physical activity during middle school PE.
School physical education plays an important role in public health. Nonetheless, there are few evidence-based, health-related, physical education programs and very little is known about how to disseminate them for widespread use. This article (a) presents background information and a review of the completed research on the SPARK (Sports, Play, and Active Recreation for Kids) programs for elementary and middle schools (1989–2000) and (b) describes the ensuing efforts to disseminate those programs nationally (1994–present). The programs have three important features: an active curriculum, staff development, and follow-up support. Efforts to disseminate the programs nationally have required substantial collaboration among university, public school, and private sector personnel. Procedures used in SPARK may serve as models for others interested in researching and disseminating physical education curricula through staff development.
Habitual physical activity in children is related to physical fitness and appears to mediate cardiovascular disease (CVD) risk factors. We studied the physical activity patterns and associated variables of a large bi-ethnic cohort of 4-year-old children from low to middle socioeconomic families. Trained observers coded the behavior of 351 children (150 Anglo-American, 201 Mexican-American; 182 boys, 169 girls) during two 60-minute home visits and two unstructured recesses lasting up to 30 minutes each at 63 different preschools. Findings indicated that although children were much less active at home, there were low but significant correlations between their activity patterns at home and during recess (r = .13). Children who had activity-promoting toys at home also tended to have them available during preschool recess (r = .20). Ethnic differences were evident for both activity and environmental variables. Mexican-American children were less active than Anglo children at home (p less than .002) and during recess (p less than .03), thus adding to the adult literature that has found Mexican-Americans to be less active than Anglos, and supporting to the notion that physical activity life-style habits may be established in early childhood. In both settings, Mexican-American children spent more time in presence of adults (home, p less than .04; recess, p less than .03) and had access to fewer active toys (home, p less than .001; recess, p less than .05). Gender differences were also evident for both activity and environmental variables.(ABSTRACT TRUNCATED AT 250 WORDS)
Although the term "behavioral epidemiology" has been used in the literature since the late 1970s, it has not been clearly defined. A behavioral epidemiology framework is proposed to specify a systematic sequence of studies on health-related behaviors, leading to evidence-based interventions directed at populations. The phase are: 1--establish links between behaviors and health; 2--develop measures of the behavior; 3--identify influences on the behavior; 4--evaluate interventions to change the behavior; 5--translate research into practice. Mature research areas are expected to have more studies in the latter phases. Recent volumes of four journals (Annals of Behavioral Medicine, Health Psychology, Journal of Nutrition Education, Tobacco Control) were audited, and empirical studies were classified into these phases. Phase 3 studies were common (identifying influences on behaviors; 27% to 50%), and Phase 2 studies were least common (measurement; 0% to 15%). Annals of Behavioral Medicine and Health Psychology were low on Phase 4 (intervention studies; 9% and 11%, respectively). The Journal of Nutrition Education was the only journal reviewed that had a substantial number (20%) of Phase 5 studies (translating research into practice). The behavioral epidemiology framework can be used to evaluate the status of research on health behaviors and to guide research policies.
Non‐alcoholic fatty liver disease (NAFLD) is a common metabolic disorder whose incidence among US adults exceeds 30%. While NAFLD manifests as benign hepatic steatosis in most patients, in about 20% of patients it assumes a much more aggressive form – non‐alcoholic steatohepatitis (NASH). The mechanisms that control the switch from benign steatosis to NASH are poorly understood, but were suggested to depend on ER stress. To query the role of ER stress in NASH development and establish a proper mouse model for studying the disease, we fed high‐fat diet (HFD) to MUP‐uPA mice, which are prone to liver ER stress due to hepatocyte‐specific urokinase plasminogen activator (uPA) expression. Placing these mice on HFD triggered full‐blown NASH within 3–4 months and most of the NASH‐afflicted mice progressed to develop hepatocellular carcinoma (HCC), the most common form of liver cancer whose incidence and development rates greatly increase with steatohepatitis. Both NASH and HCC development in MUP‐uPA mice depend on ER stress and are associated with persistent activation of sterol response element binding proteins (SREBP) 1 and 2. SREBP1 activation drives de novo lipogenesis (DNL) and cholesterol biosynthesis in HFD‐fed MUP‐uPA mice remains elevated without any sign of feedback inhibition mechanisms that control SREBP2 activation in tissue culture cells. DNL and cholesterol synthesis are also chronically elevated in NASH patients and the hepatic accumulation of free cholesterol was suggested to be a key switch from simple steatosis to NASH. While investigating the mechanism by which ER stress leads to persistent SREBP activation, we uncovered a previously unknown pathway in which caspase‐2 (Casp2) leads to constitutive activation of site 1 protease (S1P), which initiates SREBP cleavage activating protein (SCAP)‐independent SREBP activation. Of note, genetic ablation or pharmacological inhibition of Casp2 in MUP‐uPA mice blocks NASH development by preventing hepatic steatosis. Casp2 ablation in both MUP‐uPA and BL6 mice also prevents HFD‐induced adipocyte hypertrophy and increases energy consumption. None of the effects of Casp2 on liver lipid metabolism are related to cell death. The NAFLD/NASH epidemic was also suggested to be associated with increased consumption of fructose, which is a major constituent of high‐fructose corn syrup (HFCS), the main sweetener and a general food additive in the US. Increased consumption of HFCS has been linked to elevated risk of developing HCC, pancreatic and colon cancer. Indeed, feeding MUP‐uPA mice a high‐fructose diet (HFrD) results in NASH and HCC development even without the peripheral obesity that accompanies HFD consumption. Although fructose was believed to give rise to hepatic steatosis through preferential uptake and direct incorporation into the glycolytic pathway in hepatocytes, recent results indicate that the first site of fructose metabolism is the small intestine. Correspondingly, we found that fructose gives rise to NASH and HCC by first disrupting the intestinal epithelial barrier, evoking an inflammatory response that drives both NASH and HCC development. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
With the abundance of literature on cardiovascular disease (CVD) prevention during childhood, recommendations for restricted dietary sodium and fat intakes during infancy and childhood are both advocated for preventive health care and criticized because the safety is undetermined. Dietitians, nurse practitioners, and pediatricians were surveyed to determine what dietary recommendations they give to parents and what source of information most influenced their decisions. A fourth group, pediatricians with particular expertise in nutrition, were surveyed as well. The overall response rate was 76%, with a total usable sample of 252. In all professional groups, 54% had no preference for any one commercially prepared formula. More importance was given to sodium content than to fat composition of formulas. On the choice of whole, low-fat, or non-fat milk for both 1- and 6-year-old children, professional groups differed significantly. Dietitians and the subgroup of pediatricians with nutrition expertise were more likely to recommend milk with higher fat content than other professional groups. Recommendations for both sodium- and fat-modified diets for children depended on CVD risk, and opinions varied between groups. Pediatricians and nurse practitioners were more likely to recommend dietary modifications for children with higher CVD risk. The variation in dietary recommendations within and between professional groups strongly indicates the need for research on the safety and efficacy of dietary restrictions in childhood. J Am Diet Assoc 88:1417, 1988.
SALLIS, J. F., J. J. PROCHASKA, and W. C. TAYLOR. A review of correlates of physical activity of children and adolescents. Med. Sci. Sports Exerc., Vol. 32, No. 5, pp. 963–975, 2000. Background Understanding the factors that influence physical activity can aid the design of more effective interventions. Previous reviews of correlates of youth physical activity have produced conflicting results. Methods A comprehensive review of correlates of physical activity was conducted, and semiquantitative results were summarized separately for children (ages 3–12) and adolescents (ages 13–18). The 108 studies evaluated 40 variables for children and 48 variables for adolescents. Results About 60% of all reported associations with physical activity were statistically significant. Variables that were consistently associated with children's physical activity were sex (male), parental overweight status, physical activity preferences, intention to be active, perceived barriers (inverse), previous physical activity, healthy diet, program/facility access, and time spent outdoors. Variables that were consistently associated with adolescents' physical activity were sex (male), ethnicity (white), age (inverse), perceived activity competence, intentions, depression (inverse), previous physical activity, community sports, sensation seeking, sedentary after school and on weekends (inverse), parent support, support from others, sibling physical activity, direct help from parents, and opportunities to exercise. Conclusion These consistently related variables should be confirmed in prospective studies, and interventions to improve the modifiable variables should be developed and evaluated.
No abstract is provided for this article.
An extensive body of knowledge documents the powerful influence that physical activity exerts on the public’s health.1–4 This body of knowledge has grown dramatically over the past half-century, and it is now well-established that physical activity produces a wide range of health benefits in essentially all segments of the population.1,3,5–9 Accordingly, over the past several decades, public health organizations across the world have increasingly recognized the importance of physical activity.10,11 In the United States, this expanding public health role is perhaps best exemplified by the Physical Activity Guidelines for Americans, which were first released in 2008 and then updated in 2018.12,13 These guidelines include detailed physical activity recommendations for population subgroups ranging from preschoolers to older persons. Most Americans do not fully meet the federal physical activity guidelines14 and, consequently, well-resourced public health initiatives are needed to increase physical activity in the US population. Surveillance is an essential component of public health planning and practice, as it provides ongoing, systematic collection, analysis, and interpretation of outcome-specific data for use in planning, implementation, and evaluation of public health activities. As public health agencies have recognized the importance of physical activity, they have included physical activity monitoring in public health surveillance systems. In contrast to other health behaviors, such as diet and tobacco use, physical activity is a relatively recent focus of public health, and many gaps still exist in surveillance of physical activity. This commentary makes the case for why and how to strengthen physical activity surveillance in the United States. The specific purposes of the commentary are to (1) highlight the strengths and limitations of current physical activity surveillance in the United States, (2) summarize recommended actions for enhancement of physical activity surveillance, and (3) call for actions across multiple societal sectors to support creation of robust physical activity surveillance in the United States.
